Cadillac Repair: AC Blower, bristle brush, air presure

Question
I have a 1991 cadilac fleetwood sedan. A/C blows cold but very little air presure. The fan does cycle up through all three speeds but at high speed there is little flow. The people in the back seat will never get cooled off. Any thoughts on what I can Check?

Answer
Hi Michael, Some things to check when you are haveing poor air flow are to make sure the air doors are working correctly so that the air does come out where you want it even if it is weak. If not then an air door motor might be bad and not allowing air to come out at all. You already verified fan speed because you said that the air sound changes as the speed is increased on the climate control panel.

    That leaves us with an obstruction through the heater cor or evaporator core. It could have some blockage because a mouse is useing that area to store things or the evaporator core could have a leak and the oil leaking out is causeing debris to stick to the core and impede to airflow through it. Fortuneately there is a simple way to tell if this is happening. Open the hood and you will see a plastic panel on the passengers side below the weatherstrip. Remove the retainer on each end and remove the panel. Next you will see the power module on the RH side that has a square connector on it. Remove the connectors and also the two 7mm bolts that hold it on. After removeing the power module shine a flashlight into the hole and you will see the evaporator core for the a/c. Most times what happens is if the core hasn't been replaced yet it will be leaking oil and will have debris stuck to it restricting the airflow. If that is the case you could try washing the core with a sprayer on your garden hose, blow compressed air on it, use a soft bristle brush(not metal bristles)...whatever works to get the stuff off. Your other options if you can't clean it is take it to your mechanic so he can do that or just replace the evaporator core and then you will have you cold air back. If however you find a "mouse nest" in there just vacuum out what you can and hopefully that will get the air flowing again.

    Hope that helps and let me know if I can be anymore assistance to you. Bill